Improvement in registering steam-gauges



E. H. ASHCHOFT.

y.Improvement in Registering Steam Gauges. N0123,355.

Patented Feb. 20, 1872.l

UNrrnn Srn'rns EDVARD H. ASHOROFT, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN REGlSTERlNG STEAM-GAUGES.

Specification forming part of Letters Patent No. 123,855, dated February20, 1872.

Specification describing a certain Improvement in ltecordin gSteam-Pressure Gauges, invented by EDWARD H. ASHCROFT, of Boston, intlie county ot' Sutolk and State 'of Massachusetts.

This invention relates to that class of steamgauges which are intendedto indicate at all times the pressure ot the steam within the gen eratorto which they are attached, and at the same time to indicate and recordany excess of pressure over and above that which the engineer is allowedto carry as a maximum 5 and it consists in the combination andarrangement of some of the parts of which it is composed, as will bemore fully explained hereinafter.

The drawing shows a sectional elevation of the steam-gauge, with theindicating-dial'removed for the purpose of showing the operating parts.

The importance of this character of gauge is well known and generallyacknowledged, and consequently need not be enlarged upon here.

In constructing these gauges, I use a case, A, ofthe form shown in thedrawing, or of any other suitable form, it being so constructed thatitsface can be covered with a dial-plate, upon'which gures are formed orplaced, so that an indicator point or iinger will at all times show tothe person in charge the amount of pressure to which each square inchofthe surface ot' the generator is subjected. ithin the case A there isplaced areservoir, A', into which the steam is conducted from thegenerator through a suitable pipe. Extending from the reservoir there isa flattened bent tube or chamber, B, which acts as a spring upon theentrance of the steam into it, its outer end being attached, by means ofa link, B1, to the outer end of a sector-arm, B2, the opposite end ofwhich has teeth formed upon its periphery for the purpose ot' meshinginto a pinion upon the shaft which carries the index-finger or pointerupon the outside of the dial, whichat all times enables the attendant tosee at a glance the amount of pressure he is carrying. The parts abovedescribed are old and well known, they being in general use, andconsequently they need not,c be more particularly described here. Theparts hereinafter described are those which form the subject-matter ofthe present invention, they being used,

in combination with those heretofore alluded to, i'or the purpose ot'producing the result aimed at. For the purpose ot' enabling the novelfeatures of this gauge to be added, there is formed in the top oi' thesteam-chamber A an opening, which is covered by a iiexible diaphragm, l,said diaphragm being made of rubber or other suitable material, and heldupon the surface of the chamber by means ot' a cap, 2, and screw-bolts 33, as shown. Through the center of the cap 2 there is an aperture, whichis large enough to admit of the passage of rod 4, which has upon itslower end a flange, the diameter of which is greater than that of theopening in the chamber A, so that when the parts are in the positionshown in the drawing no steam can pass from said chamber under thediaphragm. Surrounding the rod 4 there is a spiral spring, 5, the lowerend of which rests upon the dan ge upon the bolt 4, while its upper endrests against a plate or cap, 6, which has upon its lower surface aprojeetion, which enters the spring and holds it in position. The jointbetween the lower cap 2, the diaphragm l, and the case A is made byscrewing down the lower nuts upon the bolts 3 3, while the compressionof the spring, and consequently the amount of pressure at which the rod4 and the diaphragm will risc from the seat, are regulated by the nutsupon the outer ends of the bolts 3 3 acting upon the plate 6, the spring5, and the rod 4, upon or within which there is aknite-edge, 7, which atcertain times presses against the short arm of a bell-crank lever, 8,which is pivoted to the case A near the end of the rod 4. This leverextends from its pivoted point in one direction far enough to allow theknife-edge 7 to press upon its surface when the pressure of steam issufcient to bring them in contact, and in the other or in a verticaldirection far enough to permit a hook which is formed upon its outerreduced end to engage the teeth or notches formed upon the periphery ofa wheel, soon to be described. By referring to the drawing, it will beseen that the upper or outer end of lever 8 is very much reduced inthickness, in order that it may form a spring and have a hook upon itsend, as shown. At some suitable point between the pivotal point of thelever S and its upper end there is attaehed a spring, 9, for the purposeof returning said lever to its original position after it has beenoperated upon by the knife-edge 7. Near the upper portions of tlie caseA there is affixed a ratchet-wheel, 10, it being so arranged withreference to the lever S that the hook upon its upper end will readilyengage the teeth upon its periphery, and cause the wheel to partiallyrotate when the short arm of the lever is raised. This wheel is to behung upon a shaft, which has its bearings in a frame,

ll; or it may be arranged in any other suitable manner which will permitthe shaft to rotate with the wheel. Upon that portion of this shaftwhich protrudes through the dialplate of the gauge there is affixed anindicator-hand, which, each time the steam has been allowed to attain apressure greater than the amount prescribed, will, as a consequence, beturned the distance which the action of the hook upon thelever 8 willcarry it, the figures being ar 1anged upon the dial to correspond withthe movements of said hand or pointer. To prevent the indicator frombein g turned backward, and thus a false record obtained, a spring, I2,is pivoted to the case A, as shown, its outer end resting upon andengaging with the teeth of the wheel l0, which will at all times preventa backward movement of such wheel. The arrangement of the parts lastdescribed, and their relation to the other parts of the gauge, are suchthat, while the gauge proper will at all times indicate the pressure ot'steam in the generator, the parts which constitute the present inventionwill not be moved from the position in which they are set until thepressure has exceeded the limits prescribed by the proper authority; butso soon as that limit is exceeded, the rod 4 will be raised by thepressure upon the diaphragm 5, andthe knifeedge 7 upon its upper endwill come in contact with the short arm of the bell-crank lever 8,pressing it upward, which will cause its upper end to be moved outwardfar enough to cause the wheel l0 to be moved sufficiently.

to 'carry the pointer on the end ofthe shaft to which the said wheel issecured from one figure on the dial to another, and thus the number oftimes that the excess of pressure has occurred will be accuratelyrecorded; and this record will be continued even though the other partsof the gauge should become entirely inoperative from the breaking orderangement of its parts.

The two divisions of the gauge, or the parts which indicate the ordinarypressure, and the parts which register the extraordinary pressure,although located in the same case, being entirely independent in theiraction, and not affected either by the other in their action or in theresults produced, as the mechanism which operates theregistering-pointer is only brought into use, or caused to move whenthere is an extraordinary amount of pressure, it follows that there isnot the same danger of derangement of these parts, or of theirdeterioration, that there would be in gauges in which such parts areconstantly in motion.

What I claim as my invention, and desire to secure by Letters Patent,is-

In combination with a steam-gauge, the supplementary steam-chamber, A',and pressurespring, actuating a registering index by means ot' asuitable pawl, S, and ratchet-wheel l0, for indicating cach time thepressure has been allowed to exceed a certain limit, the whole being soarranged that while the ordinary range of pressure is constantlyindicated in the usual manner, the said supplementary steam-chamber,with its dependent mechanism, is called into action for registeringextraordinary pressures.

In testimony whereof I have signed my name lto this specification in thepresence of two subscribing witnesses.

EDI/VARI) H. ASHOROFT.

IVitnesses C. F. CLAUsEN, I3. EDw. J. ErLs.

